Combining Two Types of Gratings for Simultaneous Strain and Temperature Measurement

A new optical fiber sensor made of tapered and CO
₂
-laser-notched long-period fiber gratings (LPFGs) is proposed for the simultaneous measurement of strain and temperature. Experiments are run to verify the feasibility of using the proposed sensor for the simultaneous measurement of strain and temperature. Experimental results indicate that after the two LPFGs are connected with each other, the sensitivity of CO
₂
-LPFG to strain deceases from 1.7 to 0 pm/με, and the sensitivity of the tapered LPFG remains unchanged; it is -1.4 and -1.5 pm/με. The sensitivity of resonance wavelength 1280, 1412, and 1545 nm to temperature are 80 pm/°C, 67 pm/°C, and 69 pm/°C. Simultaneous strain and temperature experiments prove the stability of proposed sensor. It is therefore strongly believed that the proposed sensor can be used to achieve simultaneous measurement of strain and temperature.